The invention relates to a machine for processing sheets, in particular, to a sheet-fed rotary printing machine, having a transporting cylinder for transporting the sheets, the cylinder having air nozzles offset in relation to one another in a direction other than an axis-parallel direction of the transporting cylinder, and having a directing configuration for directing the sheets, the configuration having air nozzles and being assigned to the transporting cylinder.
German Published, Non-Prosecuted Patent Application DE 35 36 536 A1 describes such a machine, of which the transporting cylinder is configured as a blowing-air drum and the directing configuration is constructed as a blowing plate. The blowing-air drum and the blowing plate have blowing-air nozzles, the configuration of which is not discussed in any more detail therein. As the sheet is being relieved of stressing, with the associated dissipation of its kinetic energy, the sheet is intercepted on an air cushion produced by the blowing nozzles disposed on segments of the blowing-air drum. In order for the sheet to have a larger acceleration path, it is necessary for the segments to be pivoted out.
Disadvantage of the prior art device include, on one hand, the construction of the blowing-air drum involves high outlay as a result of the segments and, on the other hand, the sheets still run in a comparatively unstable manner.
It is accordingly an object of the invention to provide a machine for processing sheets that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that ensures that the sheets run in a particularly stable manner.
With the foregoing and other objects in view, there is provided, in a sheet processing machine having a transporting cylinder for transporting sheets, the transporting cylinder having a longitudinal axis, in accordance with the invention, a sheet transporting device includes air nozzles disposed in the transporting cylinder and a directing configuration for directing the sheets along the transporting cylinder. The air nozzles are disposed offset in relation to one another in a direction at an angle to the longitudinal axis. The directing configuration has directing air nozzles and cooperates with the transporting cylinder to transport the sheets between the directing configuration and the transporting cylinder. The air nozzles and the directing air nozzles include throttled air nozzles and unthrottled air nozzles. Preferably, the sheet processing machine is a sheet-fed rotary printing machine.
It is possible to have different sheet-stabilizing combinations of the throttled air nozzles with the unthrottled air nozzles. The throttled air nozzles having a comparatively steep characteristic curve of pneumatic action in the vicinity of the nozzles and the unthrottled air nozzles having a comparatively shallow characteristic curve of pneumatic action in the vicinity of the nozzles.
In accordance with another feature of the invention, the transporting cylinder only has the throttled air nozzles and the directing configuration has both the throttled air nozzles and the unthrottled air nozzles.
In accordance with a further feature of the invention, the transporting cylinder only has the throttled air nozzles and the directing configuration only has the unthrottled air nozzles.
In accordance with an added feature of the invention, the transporting cylinder only has the unthrottled air nozzles and the directing configuration only has the throttled air nozzles.
In accordance with an additional feature of the invention, the transporting cylinder only has the unthrottled air nozzles and the directing configuration has both the throttled air nozzles and the unthrottled air nozzles.
In accordance with yet another feature of the invention, the transporting cylinder has both throttled air nozzles and the unthrottled air nozzles and the directing configuration only has the throttled air nozzles.
In accordance with yet a further feature of the invention, the transporting cylinder has both some of the throttled air nozzles and some of the unthrottled air nozzles and the directing configuration has the rest of the throttled air nozzles and the rest of the unthrottled air nozzles.
In accordance with yet an added feature of the invention, the directing air nozzles include the throttled air nozzles and the unthrottled air nozzles.
Of the six variants mentioned, those in which the directing configuration has throttled air nozzles and unthrottled air nozzles are preferred.
Configurations of the air nozzles as blowing-air and/or suction-air nozzles that are described hereinbelow are possible in combination with all six previously mentioned variants of associated the air nozzles to the transporting cylinder and to the directing configuration.
In accordance with yet an additional feature of the invention, the throttled air nozzles of the transporting cylinder and/or the unthrottled air nozzles of the transporting cylinder may be suction-air nozzles. As such, the transporting cylinder is referred to as a suction-air drum.
The transporting cylinder is preferably configured as a blowing-air drum. As such, the throttled air nozzles of the transporting cylinder and/or the unthrottled air nozzles of the transporting cylinder are configured as blowing-air nozzles. It is preferable for both the throttled and the unthrottled air nozzles of the transporting cylinder to be configured as blowing-air nozzles.
The throttled air nozzles of the directing configuration and/or the unthrottled air nozzles of the directing configuration may be suction-air nozzles. As such, the directing configuration is referred to as a suction-air box, bar, or rake.
The directing configuration is preferably configured as a blowing-air box, bar, or rake. As such, the throttled air nozzles of the directing configuration and/or the unthrottled air nozzles of the directing configuration are configured as blowing-air nozzles. It is preferable for both the throttled and the unthrottled air nozzles of the directing configuration to be configured as blowing-air nozzles.
In accordance with again another feature of the invention, at least one of the air nozzles and the directing air nozzles have joints, and the throttled air nozzles are movably mounted in the joints.
In accordance with again a further feature of the invention, the throttled air nozzles include springs and are resiliently mounted in at least one of the air nozzles and the directing air nozzles by the springs.
In accordance with again an added feature of the invention, there is provided at least one air throttle fluidically communicating with at least one of the throttled air nozzles and the directing air nozzles. Each of the abovementioned throttled air nozzles of the directing configuration and/or the transporting cylinder can be connected pneumatically to an air-pressure generator through an air throttle.
With the air-pressure generator preferably being configured as a positive-pressure generator that generates blowing air, the throttled air nozzle or each throttled air nozzle connected to the positive-pressure generator through the air throttle is a throttled blowing-air nozzle.
With the air-pressure generator possibly being configured as a suction-air generator, or a negative-pressure generator that generates a vacuum, the throttled air nozzle or each throttled air nozzle connected to the negative-pressure generator through the air throttle is a suction-air nozzle.
The air throttle may be integrated, at a distance from a respective throttled air nozzle, in an air-directing system to which the throttled air nozzles are connected. The integration is favorable if the air throttle provided is one that is connected pneumatically to a plurality of the throttled air nozzles at the same time through the air-directing system. The air throttle and the air nozzle throttled by the air throttle may also form a structural unit in the form of a throttle nozzle. In the last-mentioned case, each of the throttled air nozzles (throttle nozzles) is assigned a dedicated air throttle that is disposed in the throttled air nozzle (throttle nozzle).
In accordance with again an additional feature of the invention, a loose-fill column is located in the air throttle as a constituent part of the air throttle. The loose-fill elements of the loose-fill column form flow resistances for the suction air or blowing air flowing through the air throttle and generated by the air-pressure generator.
In accordance with still another feature of the invention, an air-filter-like throttle element is located in the air throttle as a constituent part of the air throttle. The throttle element forms a flow resistance for the suction air or blowing air. The throttle element is, for example, a textile layer that may be woven or non-woven. It is also possible, however, for the throttle element to be a porous and, thus, air-permeable sponge made of foamed plastic.
In accordance with still a further feature of the invention, the air throttle is provided with air weirs that project into the flow path of the suction air or blowing air and bound vortex chambers.
In accordance with still an added feature of the invention, the air throttle is a helical air channel.
In accordance with still an additional feature of the invention, the air throttle is configured as a so-called perforated-plate labyrinth and includes perforated plates disposed one above another and vortex chambers located between the plates.
With the objects of the invention in view, there is also provided a sheet processing machine having a transporting cylinder for transporting sheets, the machine including air nozzles disposed in a transporting cylinder having a cylinder longitudinal axis and a directing configuration for directing the sheets. The air nozzles are disposed offset in relation to one another in a direction at an angle to the cylinder longitudinal axis. The directing configuration has directing air nozzles and cooperates with the transporting cylinder to transport the sheets between the directing configuration and the transporting cylinder. The air nozzles and the directing air nozzles include throttled air nozzles and unthrottled air nozzles.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a machine for processing sheets, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.